Separating different contributions to the crystal-field parameters using Wannier functions.

We discuss the calculation of crystal-field splittings using Wannier functions and show how contributions to the crystal-field splitting that are due to hybridization with different ligand states can be separated from the bare Coulomb contribution by constructing sets of Wannier functions incorporating different levels of hybridization. We demonstrate this method using SrVO3 as a generic example of a transition metal oxide. We then calculate trends in the crystal-field splitting for two series of hypothetical tetragonally distorted perovskite oxides and discuss the relation between the calculated 'electrostatic' contribution to the crystal field and the simple point charge model. Finally, we apply our method to the charge disproportionated 5d electron system CsAuCl3. The proposed procedure elucidates the way in which the negative charge transfer energy in this material leads to a reversal of the p-d ligand contribution to the crystal-field splitting such that the eg states of the nominally Au(3+) cation are energetically lower than the corresponding t2g states.

Linear magnetoelectric effect by orbital magnetism.

We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an applied electric field. Using LiFePO(4) as a model compound we show that spin-orbit coupling partially lifts the quenching of the 3d orbitals and causes small orbital magnetic moments (µ((L)) ≈ 0.3 µ(B)) parallel to the spins of the Fe(2+) ions. An applied electric field E modifies the size of these orbital magnetic moments inducing a net magnetization linear in E.

Magnetic excitations in the low-temperature ferroelectric phase of multiferroic YMn2O5 using inelastic neutron scattering.

We studied magnetic excitations in a low-temperature ferroelectric phase of the multiferroic YMn(2)O(5) using inelastic neutron scattering (INS). We identify low-energy magnon modes and establish a correspondence between the magnon peaks observed by INS and electromagnon peaks observed in optical absorption [A. B. Sushkov et al., Phys. Rev. Lett. 98, 027202 (2007).]. Furthermore, we explain the microscopic mechanism, which results in the lowest-energy electromagnon peak, by comparing the inelastic neutron spectral weight with the polarization in the commensurate ferroelectric phase.

Relation of family responsibilities and gender to the productivity and career satisfaction of medical faculty.

BACKGROUND: Studies have found that female faculty publish less, have slower career progress, and generally have a more difficult time in academic careers than male faculty. The relation of family (dependent) responsibilities to gender and academic productivity is unclear. OBJECTIVE: To describe dependent responsibilities by gender and to identify their relation to the aspirations, goals, rate of progress, academic productivity, and career satisfaction of male and female medical school faculty. DESIGN: 177-item survey questionnaire. SETTING: 24 randomly selected medical schools in the contiguous United States. PARTICIPANTS: 1979 respondents from a probability sample of full-time academic medical school faculty. MEASUREMENTS: The main end point for measuring academic productivity was the total number of publications in refereed journals. Perceived career progress and career satisfaction were assessed by using Likert scales. RESULTS: For both male and female faculty, more than 90% of time devoted to family responsibilities was spent on child care. Among faculty with children, women had greater obstacles to academic careers and less institutional support, including research funding from their institutions (46% compared with 57%; P < 0.001) and secretarial support (0.68 full-time equivalents compared with 0.83 full-time equivalents; P = 0.003), than men. Compared with men with children, women with children had fewer publications (18.3 compared with 29.3; P < 0.001), slower self-perceived career progress (2.6 compared with 3.1; P < 0.001), and lower career satisfaction (5.9 compared with 6.6; P < 0.001). However, no significant differences between the sexes were seen for faculty without children. CONCLUSIONS: Compared with female faculty without children and compared with men, female faculty with children face major obstacles in academic careers. Some of these obstacles can be easily modified (for example, by eliminating after-hours meetings and creating part-time career tracks). Medical schools should address these obstacles and provide support for faculty with children.